Nuxt•5w ago

AsyncLocalStorage server side

I've been looking at the documentation for the experimental feature asyncContext. I'm confused if this is a client side only feature or if it's supposed to work server side to? My understanding was AsyncLocalStorage was on the node side, not the browser side. I'm trying to use it in a server side util to get some data from the db with the logged in user information but useNuxtApp is undefined there. I'm not exactly sure what to use. I'm calling this from a defineEventHandler api route which I thought it should work in.

2 Replies

kapa.ai•5w ago

Hi @bnason. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- The asyncContext experimental feature in Nuxt is indeed designed to work on both the client and server sides, with a focus on server-side functionality. You're correct that AsyncLocalStorage is primarily a Node.js feature, and Nuxt has made efforts to support it in server-side contexts. According to the Nuxt documentation on experimental features (https://nuxt.com/docs/guide/going-further/experimental-features#asynccontext), enabling asyncContext allows "native async context to be accessible for nested composables in Nuxt and in Nitro." This feature is particularly useful for server-side operations. To enable this feature, you need to add the following to your nuxt.config.ts:

export default defineNuxtConfig({
  experimental: {
    asyncContext: true
  }
})

export default defineNuxtConfig({
  experimental: {
    asyncContext: true
  }
})

However, it's important to note that useNuxtApp is not directly available in server-side utility functions or API routes. Instead, for server-side operations, especially within defineEventHandler, you should use the event object to access context-related information. For accessing user information or other context data in a server-side util or API route, you might want to consider using Nitro's utilities. The Nitro documentation (https://nitro.unjs.io/guide/utils#async-context-experimental) mentions that you can use useEvent() (which is auto-imported) in any utility or composable to access the request event without manually passing it along, once the asyncContext feature is enabled. Here's an example of how you might use this in a server-side API route:

export default defineEventHandler(async (event) => {
  // Use useEvent() to access the event context
  const event = useEvent()
  
  // Now you can access user information or other context data from the event
  // For example, if you've set user information in the event elsewhere:
  const user = event.context.user
  
  // Use this information to fetch data from the database
  const data = await fetchDataFromDB(user)
  
  return data
})

export default defineEventHandler(async (event) => {
  // Use useEvent() to access the event context
  const event = useEvent()
  
  // Now you can access user information or other context data from the event
  // For example, if you've set user information in the event elsewhere:
  const user = event.context.user
  
  // Use this information to fetch data from the database
  const data = await fetchDataFromDB(user)
  
  return data
})

Remember that this feature is experimental, so its behavior might change in future Nuxt versions. Also, make sure you're using a recent version of Nuxt that supports this feature. If you're still encountering issues, it might be helpful to check if you're using the latest version of Nuxt and if there are any specific requirements or limitations for your particular use case. Nuxt Experimental Features Documentation (https://nuxt.com/docs/guide/going-further/experimental-features#asynccontext) Nitro Async Context Documentation (https://nitro.unjs.io/guide/utils#async-context-experimental) ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•5w ago

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AsyncLocalStorage server side